Convex Hull

Graph Theory Demonstration : Given a set of points, determine which points lie on the "outer perimeter".

1. Pick the points by clicking on the black rectangle area of the applet.

2. Choose which algorithm you want to use, then click on the GO button.

3. Choosing additional point during the calculation will cause the program to recalculate from the beginning. You may also choose additional points and recalculate the result after each execution. Or you can click on the CLEAR button to clear the screen and pick new points at any time.

 

There are many solutions to the convex hull problem. And I choose to implement two of them. The purpose is to compare the speed and techniques of each algorithm in finding the hull. If you want the source code, here it is

 
Algorithm Descriptions Best Case
Quick Hull Algorithm Recursive solution to split the points and check which points can be skipped and which points shall be keep checking. O(n log n) 
Brute Force Algorithm Compare all lines combination with other points and find out is the line member of the hull. O(n pow 3) 
 

Programmed by Jeff So.


UPDATE :

The above program was done for my university project back in 1996.
Click here for a much more detail description of the problem and the solution.
 


 

Send comments to jcs@piler.com